Regulating system



June 10, 1930.A J.. A. SPENCER REGULATING SYSTEM Filed March 31 1928 GNQMONQNOQOOMNMQOQ 00000000000 Q 454909055550,

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Patented June 10,1930 A' uur-ED STATES JoHN A. SPENCER, or anvnan,

PATENT er1-Ica MASSACHUSETTS, 'ASSIGNOB TO RAYTHEON, INCWCF REGULATING SYSTEM Application sled March 31,

' My invention relatesto a regulating system for maintaining a predetermined gas pressure in a supply line. It has particular application to the gas supply system in the manufacture of electrical discharge apparatus but may be used in any other system in which the gas supply must be kept constant.

lIn the manufacture of electrical discharge apparatus it is customary to remove all foreign gases Vfrom the container enclosing the discharge apparatus and to fill this container with a gas or mixture of gases at a certain pressure. In many kinds of devices, especially of the gaseous conductiontype, it isy very important that the gas filling beas pure as possible and the pressure of the gas be at a predeterminedY value. Thus in gaseous conduction devices, as'glow lamps and rectiliers, the gases customarily used are of the inert monatomic up although other gases may also be use gases is usually very low compared `with atmospheric pressure and may vary from a few centimeters of mercury downto a fractionof a millimeter of mercury.

In the manufacture of electric discharge apparatus, the device is usually exhausted of its .air content in one or more stages.y H

t drogen is then admitted to wash out the interior or foreign gases. At the samel time the apparatus is heated as by baking, or, in the case of the metallic portions, by high frequency induced currents whereby any adsorbed and occluded gases are released. All of these gases, including hydrogen, are pumped out with possibly another washing of hydrogen gas and finally the hydrogen is pumped out. This last exhausting of ,the

ydrogen is usually accomplished in several stages, four or more stages often being the case. The device in its exhausted condition is then connected to a reservoir containing the chemically pure gas or gases used in filling.

All of these operations of exhausting and washing are carried on withthe usual well l known machines that are in use in the manufacture of thermionic vacuum ltubes. `In those devices, asis well known, there are two round tables, one of them being stationary,

The pressure of these,

192s. seria; No. 266,441.

the other one rotating. The rotating table carries the apparatus to be exhausted while the stationary table has connected to it'the exhausting pumps, hydrogen supply tanks and gas filling tanks. The apparatus to be exhausted is turned from one operation to the other operation, an oil seal between tables preventing any leaks into or out of the junction between the movable and stationary tables. Y

In the commercial manufacture of gas filled electric discharge apparatus, it often happens that a leak .develops in the exhaust system whereby the tube or other envelope containing the electric apparatus is either not exhausted at all or is. insuiiciently exhausted. In any event, under such conditions, when a tube finally comes to the position for filling with the gas, it may happenthat there is more pressure in the tube than in the gas supply line in which case the impure gases from the tube will contaminate the gases used for filling purposes.-

Since the gases used for filling are costly, especially so because of the great purity re- .quired and since lthe entire gas supply system must be cleaned out and reexhausted if it .is'contaminated, it may readily be seen that an improperly exhausted bulb may ordinarily cause considerable trouble.

The pressure in the electric discharge apparatus, as for example the tube, may also be too low to `do the above in which case the z apparatus itself will be defective because of its impure gas contents. Furthermore, the as filling of the tube must be adjusted to tlie predetermined value `within rather .fclose limits. It is commercially impractical to use any of the ordinary valves orl have an operatorturn olf the gas supply'when the filling is completed.

My invention aims at providing means whereby any impure gases in the electrlc discharge aparatus, because of defective exhaustion, will not contaminate the gas supply system and 'also provides meanswhereby Ithe discharge apparatus is automatically filled to the correct pressure by means of a supply line which is automatically maintained at the correct gas pressure. My invention further provides means whereby if the gas pressure in the supply tank becomes too low, a visible signal is given. Other and further advantages of my invention will become manifest as it is described in further detail.

Referring to the drawings, Figure 1 shows my improved regulator in detail with certam portions in section.

Figure 2 is a detailed view of a valve in the system.

Numeral 22 is the electric discharge apparatus which is exhausted, washed out, and then filled as described in general terms above. rTube. 22 has the tubulature 24 inserted into the rubber connected pipe 25 of movable table of any of the well known thermionic vacuum tube machines. Table 30 rotates 22 from one position to another step by step, stopping at every position. Assuming that the tube has been lexhausted of its air content and washed with hydrogen, Jfreed of the occluded and adsorbed gases, tube 22 is now shown in this figure as 1n the filling position and connected to supply pipe 33, having just moved from its prevlous exhausted position 32. With the tube in the position shown, gas comes from container or primary gas supply 1, through cock 2, through diiusion tubes 5 and 6, then on to reservoir or secondary gas supply 13, through Geissler tube 14 and down to supply pipe 33 into tube 22. IThe course of the gas through diffusion tubes 5 and 6 is determined by the closing of cocks 3 and 4.

.Diffusion tube 5 comprises an inner tube 51, a plug of porous carbon 53 closing the end ot tube 51, and a pool of mercury 52 in outer tube 54. This pool of mercur is just deep enough so that the surface is a ove the bottom of inner tube 51. This prevents any back iow of air or other gases into primary source 1. rl`he gas in primary source 1, be-s ing at somewhat less than atmospheric pres sure, may readily diffuse through plug 53, through the mercury pool, and into outer tube 54.

Diffusion tube 6 comprises outer tube 61 connected by tube 55 to the outer tube 54 of diffusion tube 5. The outer tube 61 has a pool o'mercury 62 at the bottom. lnner tube 64 has its end closed up with a porous carbon plug 63. 7 is' a steel or iron ring floating in the mercury pool. The mercury pool and inner tube 64 are so adjusted that as ring 7 floats in the mercury, the surface of the mercury will be above the bottom of inner tube 64, thus cutting oil any gaseous communication from tube 55 to inner tube 64.

Manometer 9 has contacts 91, 92, and 93 as shown. This manometer is so adjusted that at the pressure of the gas llin desired in 22, contacts 92 and 93 are bro en. lf, however, the pressure in supply line 33 which is directly connected to secondary gas supply 13 shouldfall below the desired value, preferably about 15 mm. of mercury, the open ended mercury column is sucked up and makes contact between 92 and 93. This results in a circuit being established through solenoid 8, which is around diii'usion tube 6 and so placed that when energized it will tend to pull up ring 7. The terminals 12 of this circuit are connected to any suitable source of energy, as for example, a battery. When contacts 92 and 93 are thus connected and electro-magnet 8 is energized, ring 7 is pulled up, allowing the level of the mercury to drop below the bottom of inner tube 64. rllhus gas from primary source 1, which of: course is at a suitable pressure, is allowed to go through diifusion tubes 5 and 6 and into the supply line. lVhen the solenoid 8 is energized, a parallel circuit leading to lamp 10 is energized. This lamp which may be colored, lights up and thus visually indicates that the supply line 33 and secondary supply 13 need more gas. When the desired pressure in the supply system beyond diffusion tube 6 has been built up, the mercury column drops separating contacts 92 and 93 and opening the solenoid and lamp circuits. Magnetic ring 7, being released, drops into mercury pool and raises its level sufiiciently to cut oli the gas supply. At thesame time lamp 10 is extinguished.

rlhe secondary supply 13 may be as large as desired and is customarily made so that at v least two or more tubes 22 may be filled before its pressure drops very much. The gas goes from secondary supply 13 through Geissler tube 14 where a discharge ted by high potential transformer 15 is maintained.

rhis discharge may be maintained continu= ously, or the tube may be so connected in the circuit of solenoid 8 or 18 as to maintain the discharge only when the solenoid is energized. rihe tube might also have an ordinary switch so the operator could start it whenever he wanted. This discharge by its color visually indicates the purity of the gas if one gas alone is used. rhus, in the case of helium, the peculiar bluish green color characteristic of that gas is given. Any impurity in the gas, however slight, causes a change in the color in the Geissler tube 14.

lin case tube 22 has been improperly eX- hausted so that its gas content is higher than the gas filling should be, ity may readily be seen that as soon as this tube is connected to the supply line gas from 22 will iow back intoI the supply line. rl`his will result in a greater pressure in manometer 16 which is shown as connected between Geissler tube 14 and tube 22. Manometer 16 has contacts 161 and 162 with a mercury column so adjusted that a slight increase above the pressure desired in 22 will cause an increase in height of the closed end of the mercury column on the right hand side of the manometer and thus establish a connection between contacts 161 and 162. A battery or other source of electricity is connected at terminals 17, a cir- 19 is connected to bell crank lever 2O by means of a pin and slot as shown, so that when core 19 is pulled into the solenoid, bell crank lever 20 is turned onits pivot so as to compress rubber tube 21 against plate 23. Hence, the gas supply line will be cut oi upon the slightest increase in pressure. The action is so quick that very little gas can go back into the supply system to contaminate the gas for filling.

If desired, a one way valve similar to di'usion tube 5 may be inserted into the supply line between Geissler tube 14 andthe junction of manometer 16 and the supply line. In this way, any back current of impure gas from y tube 22 could never get to Geissler tube 14.

However, in practice manometer 16 is so sensitive that the supply line is cut off before any appreciable amount of gas can flow into it. Then it takes an appreciable pressure to get the gas throu h the porous carbon plug. To

vutilize as muc of the gas in 1 and 13 as possible it is desirable that when there is a gaseous dow from 1 to v13 and also from 13 to 22, the dow be as unimpeded as possible.

In case the supply line beyond diffusion tuloe should break or in case manometer 16 tails to function quickly enough or fails to function atall, the increased pressure due to the outside atmosphere in case oiu a break or its hack dow from 22, would cause mercur in manometer 9 to rise u toward Contact 9i and establish a contact etween 91 and 92. This would close the circuit to lamp i1 which might he colored red and would serve to indiIrl cate the state of aidairs. ith cocks 3 and i closed, it may readily he seen that no gas impurity could ever get by dinfusion tuloe 5. Hence, no matter what may happen, primary source l is always protected against. the inux ot contaminated gases.

ln case the pressure in primary source l has fallen to a very low value and in case the suction pressure in tubes 5 and 6 is too great so that the supply line after did'usion tube 6 is at too low a pressure maintaining solenoid d and lamp l0 energized, it is possible to open cocks 3 and 4 and provideadirect path. Suche,

procedure Wouldmtcourse, be very uncoon n and in practice would only be used when 1 was almost exhausted. In case a new primary source l were connected to the supply system, cock 2 would be closed-while cocks 3 and et would be open and the entire system would be exhausted so as to free it from lthe air rushing in when the old primary source was discon nected and a new one connected. The container itself has a glass seal not shown, so when it is fused to the supply line, the 'gas therein will not escape. s is customary a .in which it is desirable :from the redetermined magnetic plug is raised and allowed to break this seal.

. While I have described and illustrated my invention with respect to a sub-atmospheric pressure gas supply system in connection with an` used independently thereof. Thus, prima f source 1 and secondary supply 13 may wdll be replaced by any sort of a gas container and any sort of a reservoir in a supply system to maintain the gas at a substantially constant pressure within cxhaustlng machine, it. may be' very narrow limits. My invention could very well be applied to gas systems in which the pressure is eater than atmospheric pressure.

It will tir a simple, yet extremely sensitive system for controlling the gas pressure in a gas system which protects against leaks and which gives a visual indication of any abnormal condition.

' I claim:

l. In a gas supply system for reexhausted electric dischar e devices whic have been substantially ex austed of undesirable gases and which are to be lilled with gas of a predetermined quality and pressure, a gas supply,

controlling means for maintaining said sup ply at the redetermined pressure, means for cutting o the flow of gas in either direction between the controlled supply and the device upon connection with a device containing gas at a greater pressure than that in the suppl and means interposed between said su p y and said pressure responsive y means or continually indicating the quality of the gas owing `between said device and said supply.

2. Inl the system set forth in claim l, means operative in the event the pressure in said controlled supply drops below a predetermined value for indicating the pressure condition in said controlled supply.

3. In the system set forth in claim l, a primary gas suppl a gas pipe connecting said primary supp y to said controlled gas supply and means responsive to the varia:l tions in pressure of said controlled supply pressure for varying the gas ow from said primary source to said controlled supply for maintaining said controlled supply at said predetermined primary` gas supply7 a gas pipeA connecting said primary source to said controlled supply, means responsive to-the variations in pressure of said controlled supply from the primary supply to said controlled sup- 'Y us be seen thatI have devised l' '125 5. In the system set forth in claim 1, al

predetarmined pressure for varying the gas ow from said primary source to saideontrolled supply trolied supply at said predetermined value and further means in sai gas pipe connection operative to prevent gas How from said;- controlled source to said primary source.

n testimony Whereo I have signed myname to this specification March, 1928.

' JOHN A. SPENCER; Y

for maintaining said y con- 

